What you need to know about this term's most important Supreme Court case

It’s not the sexiest case before the Supreme Court this term, but it’s one of the biggest — and it could reshape U.S. voting rights.

The case, Gill v. Whitford, dates back to 2011, when Wisconsin Republicans in control of the state legislature used voters political leanings to redraw district lines to lock in a heavy majority of seats. Afterward, even when they finished about even with Democrats in the statewide vote, Republicans kept their majority.

It’s the first time in over a decade that the Supreme Court has considered the practice, known as partisan gerrymandering. Its impact will be enormous — in July, Justice Ruth Bader Ginsburg told an audience at Duke that the Supreme Court’s decision to hear the case was “perhaps the most important grant so far.”

VICE News talked to Michael Li, who works on redistricting and voting rights issues for the Brennan Center’s Democracy program, about how gerrymandering works and why Gill v. Whitford could dramatically reshape voting in the United States.

This case, Gill v. Whitford, centers on the recent redistricting of Wisconsin. What exactly happened?

In 2011, Wisconsin Republicans controlled redistricting for the first time in decades. The leaders of the legislature hired consultants who worked in a closed room for four months, generating map after map after map, trying to see how much more aggressive they could be in terms of giving the Republicans more seats and securing that advantage over the course of a decade.

It was really a secretive, closed-door process. Democrats never saw the maps. Republican members of the legislature were allowed to see their own district, but they weren’t allowed to see the map as a whole. And the result was a map that gives Republicans almost a 60 percent majority, even if they were less than 50 percent of the vote. And it locks that in. For Democrats to win a majority, they would have to get well over 50 percent of the vote to even break even.

So people challenged the Republican maps, and in the latest ruling a federal court found that the state’s congressional districts were the result of partisan gerrymandering and struck them down. Now, Wisconsin is arguing that partisan gerrymandering happens all the time. What will happen if Wisconsin loses?

If the court puts some limit on partisan gerrymandering and helps us understand the problem and suggests that courts will be involved in this, I think, a) advocates will have tools to the extent that legislators will still engage in mischief. But b) lawmakers will have some guidance about how to test maps and how to look at maps and how to draw fairer maps.

And if Wisconsin wins?

I think that lawmakers are going to see that as a green light to do whatever they want and they will go to town.

It’s illegal to racially gerrymander, or draw congressional districts based solely on the basis of voters’ race. If so many minority voters vote Democrat, how do you separate partisan gerrymandering from racial gerrymandering?

So race and party increasingly overlap in many parts of the country, but increasingly in the South. What you’ve seen this decade is maps that disadvantage African-Americans or Latinos in big ways in states like North Carolina and Texas. And you’ve seen the defense is, “We weren’t trying to hurt minorities. We were just trying to target Democrats, and lo and behold, they just happened to be minorities.”

People have felt that they can get away with that, because there is a sort of artificial distinction between race and politics that our jurisprudence has left us with, where if you do it on the basis of race, you’re out of bounds; if you do it on the basis of politics, you’re in bounds. And really, you know, it’s sort of really hard to untangle race and politics in the South. It’s in fact a false binary, because it’s not as though it has to be either race or politics. It can sometimes be both, sometimes fused with a dose of religion or something like that.

[This case] would end the convenient excuse that lawmakers have right now, of, “We were just trying to do this on the basis of politics.”

This interview has been edited and condensed for clarity.